Explosive composition



United States Patent 3,036,940 EXPLOSIVE COMPOSITION David A. Fletcher, Redlands, Calif., assignor to Lockheed Propulsion Company, a corporation of California No Drawing. Filed Jan. 21,1958, Ser. No. 710,380 2 Claims. (Cl. 149--78) This invention relates to improvements in new and useful compositions of matter of the liquid or gel type suitable for use as explosives and fuels for rocket motors.

Explosives differ from ordinary combustibles in that they contain both oxidizing and reducing features and require no air or other supporter of combustion in order to react. These features may be both contained in the same molecular structure, such as nitroglycerin or nitrocellulose, or they may be combined as a heterogeneous, multiphase system such as sulfur-potassium nitrate-charcoal, i.e., gunpowder.

In all instances, shipment and handling has been a problem, as the prepared explosive is usually processed and packaged prior to use, after which it must be shipped to the location where it is to be used. Shipment and handling are extremely hazardous.

Most liquid propellants are of the bi-propellant type which consists. of two strongly interacting liquids, one an oxidizer and the other a reducing agent. These, when combined under the proper conditions and ignited, burn rapidly with the liberation of much energy and gaseous products. Examples of such pairs are liquid oxygen/ gasoline, or red fuming nitric acid/dimethyl hydrazine. These liquids have the disadvantages of requiring separate storage tanks and needing complicated feed mechanisms, pumps, turbines, or pressurizing devices, and a complicated thrust chamber. In the case of liquid oxygen, it cannot be stored for any extended period, because of its low critical pressure.

Another type of liquid propellant, used to a very limited extent commercially, are the monopropellants, which are complete rocket fuels in themselves and which contain both the oxidizing and reducing features. The present invention is of this type. Examples are hydrogen peroxide, nitromethane, ethylene oxide, tetranitromethane, or solutions of an organic material such as ethyl alcohol in hydrogen peroxide or tetranitromethane. They generally have the disadvantages of (1) low energy output, e.g., hydrogen peroxide, ethylene oxide; (2) poor storage stability; or (3) sensitivity to detonation, e.g., tetranitromethane; or they may have all three disadvantages. Concentrated hydrogen peroxide, 70-95 pure, has been used to some extent to provide auxiliary power for helicopters, but it has comparatively low energy, and trace impurities or contamination may cause spontaneous detonation. Nitromethane, while stable to ambient temperature storage, is low in energy and underoxidized to the point that carbon smoke may appear in the exhaust gas. Tetranitromethane, although capable of furnishing high impulse has thus far been too sensitive to detonation to be used to any extent as a monopropellant. Feed systems for monopropellants are comparatively simple since only one material is supplied to the rocket engine.

I have discovered that explosives and monopropellants may be prepared from safe, easily handled nonexplosive constituents which may be shipped with safety to the location of use, stored indefinitely and combined in solution when use is desired. Specifically, my invention contemplates lithium perchlorate in a solvent solution, preferably, low molecular weight polar organic solvents. Such solutions, once prepared, may be readily detonated.

Unlike other solid perchlorates, such as ammonium perchlorate, potassium perchlorate and sodium perchlorate which are soluble in organic solvents to a very limited ex- 3,036,940 Patented May 29, .1 962 Grams dissolved in g. solvent Solvent 111C104 K0104 NHrClOr NaClO,

, 151.8 0.01 14.7 n-Propanol. 105. 0 0. 01 4. 0 n-Butanol- 79. 3 0.005 l. 9 Acetone 156.3 0. l6 51. 7 Diethyl ether 113. 7 insol. lnsol.

1 Solubility about like K0104.

Percent by wt.

(1) Anhydrous LiClO 62 Methanol 38 (2) Anhydrous LiClO 15 Nitromethane 70 Methanol 15 (3) Anhydrous LiClO 35 Nitromethane 35 Methanol 25 Acetone 5 Any suitable stabilizers, combustion catalysts or modifiers may be added as desired.

Compositions of the present invention, lithium perchlorate-methanol solution, for example, when employed as monopropellants, provide higher energy than any other monopropellant generally known in the art at the present time as shown by the following comparative data:

Density, Volume Remarks on Propellant System lbs/in. I 1,000 Impulse Stability 01' Performance Hydrogen peroxide 0. 050 max 7. 5 Unstable, low 0 w. impulse. Nitromethane. 0. 0412 173 7. 1 Detonates easily, smoky exhaust. Ethylene oxide- 0.032 5. 8 Stable but low vol. impulse. LiclOi-methenol 0. 0497 226 l1. 2 Stability of solsolution (62% ute and solvent concentration). excellent; ex-

haust nonsmoky, good impulse.

Specific impulse, I as used in the above table, is a parameter used in rocketry for rating energies of propellants and is the pounds thrust obtainable per poundper-second or propellant flow under a given set of conditions.

Volume impulse, which is the product of specific impulse and density, gives a rating of propellants per unit of volume. Note that ethylene oxide has a moderately good specific impulse, but a low volume impulse due to its low density.

Monopropellant compositions preferably should contain a nitroparaffin such as nitromethane which improves fluidity yet allows the least reduction in specific impulse. The solubility of lithium perchlorate in methanol changes considerably with temperature and precipitation or gel formation may occur if nitromethane or other diluent is not added.

References Cited in the file of this patent UNITED STATES PATENTS 2,783,138 Parsons Feb. 26, 1957 OTHER REFERENCES Leonard: Journal of the American Rocket Society, No. 72, December 1947, pages 10-16.

Jet Propulsion, Report prepared by the Guggenheim 5 Aeronautical Laboratory and the Jet Propulsion Laboratory, GALCIT, California Institute of Technology for the Air Technical Service Command, 1946, pages 295-296. Langes Handbook of Chemistry, 7th ed., Handbook Publishers, Inc., Sandusky, Ohio, 1949, pp. 228-229.

Tschinkel: Ind. and- Eng. Chemistry, vol. 48, No. 4, pp. 732-735, April 1956. 

2. A LIQUID MONOPROPELLANT COMPOSITION WHICH CONSISTS ESSENTIALLY OF ABOUT 15-35% BY WEIGHT OF LITHIUM PERCHLORATE IN SOLUTION WITH ABOUT 35-70% OF A LOWER NITROPARAFFIN AND ABOUT 15-25% BY WEIGHT OF METHANOL. 